diff options
Diffstat (limited to 'gas/doc')
| -rw-r--r-- | gas/doc/c-riscv.texi | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/gas/doc/c-riscv.texi b/gas/doc/c-riscv.texi index c15297e..bfbf61d 100644 --- a/gas/doc/c-riscv.texi +++ b/gas/doc/c-riscv.texi @@ -213,13 +213,23 @@ desirable. Enables or disables the CSR checking. @cindex INSN directives -@item .insn @var{value} +@item .insn @var{type}, @var{operand} [,...,@var{operand_n}] +@itemx .insn @var{insn_length}, @var{value} @itemx .insn @var{value} This directive permits the numeric representation of an instructions and makes the assembler insert the operands according to one of the instruction formats for @samp{.insn} (@ref{RISC-V-Formats}). For example, the instruction @samp{add a0, a1, a2} could be written as -@samp{.insn r 0x33, 0, 0, a0, a1, a2}. +@samp{.insn r 0x33, 0, 0, a0, a1, a2}. But in fact, the instruction +formats are difficult to use for some users, so most of them are using +@samp{.word} to encode the instruction directly, rather than using +@samp{.insn}. It is fine for now, but will be wrong when the mapping +symbols are supported, since @samp{.word} will not be shown as an +instruction, it should be shown as data. Therefore, we also support +two more formats of the @samp{.insn}, the instruction @samp{add a0, a1, a2} +could also be written as @samp{.insn 0x4, 0xc58533} or @samp{.insn 0xc58533}. +When the @var{insn_length} is set, then assembler will check if the +@var{value} is a valid @var{insn_length} bytes instruction. @cindex @code{.attribute} directive, RISC-V @item .attribute @var{tag}, @var{value} |